Wireless human interface device with integrated temperature sensor

ABSTRACT

A wireless human interface device (HID) includes an input interface module for accepting inputs from a user; a microprocessor for processing the accepted inputs; a wireless transmitter for transmitting the accepted inputs to a host; and a temperature sensor for determining the temperature of the wireless HID, wherein the microprocessor transmits the sensed temperature via the wireless transmitter to the host for displaying.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/244,631, filed Oct. 5, 2005, entitled “WIRELESS HUMAN INTERFACEDEVICE WITH INTEGRATED TEMPERATURE SENSOR,” also referred to as U.S.Patent Publication 2006-0071788 A1. U.S. patent application Ser. No.11/244,631 is incorporated by reference herein in it entirety.

FIELD OF THE INVENTION

The present invention relates generally to Human Input Devices, and moreparticularly to a wireless Human Input device with integratedtemperature sensor.

BACKGROUND OF THE INVENTION

Wireless communication is rapidly growing. For example, peripheraldevices and human interface devices (HIDs) are increasingly utilizingwireless communication, such as Bluetooth, to communicate with a hostcomputer.

Bluetooth (BT) is a wireless protocol and thus requires a radiotransmitter and radio receiver. Bluetooth integrated circuits (ICs) andother wireless chips with radios integrated on a single silicon dieoften incorporate temperature sensors used to calibrate radio circuitsacross temperature variations. Other wireless protocols, such as thosetypically operating in the 27 MHz frequency band, may operate in onedirection only, in which case only a radio transmitter is required.

In some applications in which the radio is used with a high duty cycleIC, the temperature of the die increases from the ambient temperaturedue to the high duty cycle of the IC. Hence, while the temperaturemeasurement from the temperature sensor may be good for calibrating theradio circuits, it is not an accurate measurement of the ambienttemperature. Furthermore, the radio is often embedded in a product(e.g., inside a laptop case or automobile) which can have an internaltemperature that is significantly higher than ambient temperature.

However, in a Bluetooth HID, the radio is typically used at a low dutycycle, typically less than 10%. Hence, the die temperature is notsignificantly raised above the ambient temperature. Furthermore, the HIDis typically separated from the host device and usually contains noother circuitry which would raise its internal temperature.

Therefore, in a BT HID, the die temperature is closely tracking theambient temperature. The present invention takes advantage of the abovecharacteristics of a BT HID to integrate a temperature sensor in the HIDthat substantially indicates the ambient room temperature.

SUMMARY OF THE INVENTION

In one embodiment, the invention is a wireless HID including: an inputinterface module for accepting inputs from a user; a microprocessor forprocessing the accepted inputs; a wireless transmitter for transmittingthe accepted inputs to a host; and a temperature sensor for determiningthe temperature of the wireless HID, wherein the microprocessor mayutilize the sensed temperature for calibrating the radio circuits andtransmits the sensed temperature via the wireless transmitter to thehost for displaying.

In one embodiment, the invention is a wireless integrated circuit (IC)including an input interface circuit for accepting inputs from a user; atemperature sensor for determining the temperature of the wireless IC; awireless transmitter for transmitting the inputs; and a processor forcalibrating the radio circuits responsive to the sensed temperature andcommunicating the sensed temperature to the wireless transmitter to betransmitted for display.

In one embodiment, the invention is a method for wirelessly transmittinguser inputs and temperature of a location to a host. The methodincludes: accepting inputs from a user via a human interface device(HID); transmitting the accepted inputs to the host via a wirelesstransmitter; sensing the temperature of the HID; calibrating the radiocircuits responsive to the sensed temperature; and transmitting thesensed temperature to the host for display.

In one embodiment, the wireless transmitter is a Bluetooth transmitter,and the radio circuits comprise a Bluetooth transmitter and a Bluetoothreceiver.

In one embodiment, the wireless transmitter is a 27 MHz transmitter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary block diagram of a wireless host system,according to one embodiment of the present invention;

FIG. 2 is an exemplary block diagram for a wireless transmitter,according to one embodiment of the invention;

FIG. 3 is an exemplary diagram for a PTAT diode temperature sensingcircuit; and

FIG. 4 is an exemplary diagram for a RC-oscillator-based temperaturesensor.

DETAILED DESCRIPTION

In one embodiment, the present invention utilizes the temperature sensorembedded in a Bluetooth chip to measure the ambient room temperature.The sensed temperature is then sent to the host where it can bedisplayed to the user as an additional feature of the HID product.

FIG. 1 is an exemplary block diagram of a host system including a PChost 100, a wireless keyboard 102, a wireless mouse 104, a wirelessprinter 106, a wireless camera 108, and a wireless game controller 110.The host system may also include other wireless HID devicescommunicating with the PC host 100. The PC host 100 couples to thewireless keyboard 102, the wireless mouse 104, the wireless printer 106,the wireless camera 108, and/or the wireless game controller 110 via awireless interface. The PC host 100, the wireless keyboard 102, mouse104, printer 106, camera 108, and game controller 110 support user inputoperations when the PC host 100 is either in a Basic Input Output System(BIOS) mode of operation or when in an operating system (OS) mode ofoperation. Each of the above HID devices include an input interface foraccepting inputs from a user and a wireless radio transmitter, such as,a Bluetooth transmitter for transmitting the accepted inputs to a host.The wireless radio circuitry includes some type of temperature sensor(s)that is used to calibrate the radio circuitry.

Use of the temperature sensor is most useful in a keyboard in which theBluetooth module can be placed in an area within the keyboard where itwill not be significantly affected by the user's body heat, for example,along the top edge of the keyboard where the user's hands do nottypically rest. While the invention may also be employed in other HIDS,such as a mouse, the sensor needs to be placed such that the user's handdoes not affect the temperature being sensed.

In one embodiment, in the case of a game controller, the temperaturesensor can be used to sense the hand temperature of the user who isholding the game controller, while playing a computer-based game. Thisbio feedback data may be integrated with some games to gain (or lose)extra bonus points, or become a parameter of the game.

Furthermore, the same wireless device can be used as a standalonetemperature sensing device which can be placed remotely from a hostcomputer.

FIG. 2 depicts an exemplary block diagram for a wireless transmitter. Amicroprocessor 201 provides data to be transmitted to the data modulator202. The microprocessor periodically checks temperature sensor 204 (inthis example, a diode temperature sensor) and uses a look up table 205in a memory (for example, ROM 206) to set bias current for the transmitpower amplifier (PA) 203 via the adjustable bias current source 209. Inone embodiment, the microprocessor uses a mathematical function tocalculate the bias from the temperature reading. As a result, themicroprocessor “flattens” the output power level versus the temperatureresulting in less variation of the output power over temperature.

An example of temperature sensors include a diode-based Proportional ToAbsolute Temperature (PTAT) source, which produces an output voltagesignal related to the temperature of the diode circuit. The outputvoltage signal is then measured by using an analog-to-digital converter(ADC) 207. Another example of a temperature sensor is aRC-Oscillator-based temperature sensor, in which the temperature ismeasured by comparing the frequency variation of the oscillator 208against a precision crystal oscillator (XO) 210.

FIG. 3 depicts an exemplary PTAT diode temperature sensing circuit. Thecircuit includes two PNP transistors 302 and 304 in Darlingtonarrangement to increase temperature sensitivity. The fundamentaltemperature-sensitive phenomenon is the emitter-to-base diode voltage ofeach transistor at a given current. A constant current is applied toFORCE_E. The resulting voltage on the diode (via resistors 306 and 308)is measured across SENSE_P and SENSE_N. The measured voltage isproportional to absolute temperature of the PTAT. Very often, two suchdiodes are used, and the difference between the measured voltages isused to determine the absolute temperature. The voltage is typicallymeasured using an analog-to-digital converter (ADC).

FIG. 4 shows an exemplary RC-oscillator-based temperature sensor.Low-power oscillator (LPO) 402 uses a resistor and a capacitor tocontrol the oscillation frequency. The on-chip resistors typically havefairly large variation over temperature, causing the oscillatorfrequency to be a function of temperature. ±30% variation is typicalover a typical temperature range of, for example, 0° C. to 70° C. for acommercial grade IC. Microprocessor 404 can then measure the LPOfrequency against the frequency of a crystal oscillator (XO) 406.Crystal oscillator frequency has some temperature sensitivity, but it istypically several orders of magnitude less sensitive than the LPO 402.For example, typical LPO variation may be ±30%, while XO may be ±0.002%Given that a temperature sensor typically exists in wireless (forexample, Bluetooth) ICs used in the HIDs, it can be utilized to sendtemperature data to a user. In a typical wireless communication, whenthe HID is first recognized by the host, the host requests the “reportdescriptors” from the HID. The host decodes the report descriptor todetermine the types and formats of the reports which the HID can send.The host also determines what type of data is contained in the reports.In one embodiment, the HID protocol employs “Usage Codes” to describethe types of data that will be sent in “reports” to the host device,typically a PC.

For example, in the Bluetooth HID standard, a usage code may be definedfor temperature. Thus, the microprocessor can translate the temperaturedata into the standard format as specified by the HID specification.Software running on the host may then detect the incoming temperaturedata and display it in a convenient manner to the user on the PC screen.For example, on a PC running the Microsoft Windows XP™ operating system,the temperature may be displayed in the “system tray” area typicallylocated in the lower-right corner of the screen.

Since in a wireless keyboard, the duty cycle of the wireless IC is low,the die temperature typically does not rise noticeably above ambientroom temperature. For example, the large size of most keyboards makes iteasy to place the IC within the keyboard such that the user's hands willnot affect the temperature of the IC.

Any other wireless input device may also employ the present invention.However, if the displayed temperature is intended as the ambienttemperature, the temperature of the device should not significantly beimpacted by external influences other than the ambient temperature. Inone embodiment, the microprocessor can automatically adjust for anestimated difference of the die (HID) temperature and the ambienttemperature, before the data is sent to the host, or before thetemperature is displayed. In one embodiment, the adjustment data may bestored and modified in a lookup table (for example, in a RAM) accessibleby the microprocessor.

Furthermore, specialized devices may be developed to remotely measureindoor or outdoor temperature. In these embodiments, the temperaturesensor, processing and wireless transmitter circuitry all are fabricatedon a single IC.

It will be recognized by those skilled in the art that variousmodifications may be made to the illustrated and other embodiments ofthe invention described above, without departing from the broadinventive scope thereof. It will be understood therefore that theinvention is not limited to the particular embodiments or arrangementsdisclosed, but is rather intended to cover any changes, adaptations ormodifications which are within the scope and spirit of the invention asdefined by the appended claims.

1. A wireless human interface device (HID) including: an input module configured to accept input from a human being; a temperature sensor configured to detect the temperature of at least a portion of the wireless HID; and a wireless transmitter configured to transmit the accepted input and detected temperature to a host device.
 2. The wireless HID of claim 1, wherein the wireless transmitter includes a Bluetooth transmitter.
 3. The wireless HID of claim 1, wherein the temperature sensor includes a duty cycle less then twenty percent (20%).
 4. The wireless HID of claim 1, wherein the temperature sensor is configured to detect an ambient temperature and not be affected by a temperature of the human being.
 5. The wireless HID of claim 1, wherein the temperature sensor is configured to detect changes in a temperature of the human being.
 6. The wireless HID of claim 1, wherein the host includes a computing device.
 7. A game controller comprising: a plurality of input modules configured to accept input from a human being; a temperature sensor configured to determine the temperature of at least a part of the human being; and a transmitter configured to wirelessly transmit the determined temperature to a game system.
 8. The game controller of claim 7, wherein the temperature sensor is configured to determine the relative temperature difference between the human being and an ambient temperature.
 9. The game controller of claim 7, wherein the temperature sensor is configured to determine the temperature of the hand of the human being.
 10. The game controller of claim 7, wherein the temperature sensor is configured to provide biofeedback to the game system.
 11. The game controller of claim 7, wherein the transmitter is configured to re-calibrate itself based at least in part upon the temperature detected by the temperature sensor.
 12. The game controller of claim 7, wherein the transmitter is configured to transmit the temperature to the game system in such a way as to facilitate the display of the temperature by the game system.
 13. The game controller of claim 7, wherein the transmitter is configured to transmit the temperature in a manner substantially compliant with the Bluetooth HID standard.
 14. The game controller of claim 13, wherein the transmitter is configured to transmit the temperature using a usage code.
 15. The game controller of claim 13, wherein the transmitter is configured to, in response to a request for a description of capabilities of the game controller, transmit that the game controller is capable of transmitting temperature.
 16. A keyboard comprising: a microprocessor configured to receive input data from a human being via keys; a temperature sensor configured to detect the temperature of at least part of the keyboard; and a transmitter configured to wirelessly transmit the detected temperature and data provided by the microprocessor to a host device.
 17. The keyboard of claim 16 wherein the microprocessor is configured to calibrate the transmitter responsive to the detected temperature.
 18. The keyboard of claim 16 wherein the transmitter is configured to transmit using a protocol substantially complaint with the Bluetooth protocol.
 19. The keyboard of claim 16 wherein the temperature sensor is configured to not be substantially affected by a temperature of the human being.
 20. The keyboard of claim 16 wherein the transmitter is configured to transmit the detected temperature to the host device for displaying. 